Releasing of a Titanium Clamp (Craniofix^®) Without Mechanical Defect After Craniotomy for Acute Subdural Hemorrhage

Abstract

After craniotomy, bone flap fixation can be performed using wires, sutures, microplates, and Craniofix®. Well-margined and fixed bone flaps are important not only for postoperative brain protection but also for esthetics. Herein, we report a case of cranioplasty due to bone flap dislocation by Craniofix® clamp loosening after craniotomy with acute subdural hemorrhage removal. Iatrogenic outward force during epidural drain removal adjacent to Craniofix®, insertion of the clamp around the circumference of the bone flap, increased intracranial pressure due to brain swelling and fluid collection, and external shock during postoperative patient management are thought to be the causes of bone flap dislocation. To our knowledge, this is the second reported case of craniotomy with a Craniofix® clamp release.

INTRODUCTION

After craniotomy surgery, bone flap fixation can be performed using a wire, suture, microplate, or Craniofix^®.¹,³,⁵,⁷⁾ The Craniofix^® titanium clamp was developed for fixing bone flaps after craniotomy. The cranial bone flap clamp forms a firm, positionally stable closure connecting the bone flap to the craniotomy edge.⁴,⁶⁾ When using a titanium clamp system, the 3 clamps should be placed at 120° intervals around the edge of the flap to secure tight fixation of the craniotomy flap.⁵⁾ Moreover, microplates and screws provide fit-shaped bone fixation along the groove while avoiding definite palpable prominence of the scalp.²⁾ Defective Craniofix^® clamps, incorrect perioperative clamp positioning, increased intracranial pressure (ICP) due to brain swelling and fluid collection, and external shock during postoperative management are considered to cause bone flap dislocation. It may be better to use Craniofix^® and other methods simultaneously for bone flap fixation.

CASE REPORT

A 72-year-old male patient underwent craniotomy with hematoma removal for acute subdural hemorrhage due to head trauma caused by slipping. Upon admission, neurological examination was performed, revealing a Glasgow Coma Scale (GCS) score of 113, pupil 8 mm fixed/4 mm fixed, and motor grade 1. After removing the subdural hematoma, the bone flap was fixed to the mother bone using three Craniofix^® 16-mm titanium clamps (FIGURE 1). We did not proceed with decompressive craniectomy because the ICP was not very high, and the brain swelling was not severe.

FIGURE 1. Initial and post craniotomy images.

(A) Initial brain CT. (B, C) Post craniotomy brain CT. There was no brain swelling, hydrocephalus, and fluid collection. Also, there was no clamp dislocation and bone flap was well aligned. (D) Post craniotomy skull X-ray. Epidural drain (yellow arrow) was inserted adjacent to superior titanium clamp.

One day postoperatively, brain computed tomography (CT) confirmed that the bone flap was fixed using Craniofix^®, and the hemovac was removed 2 days postoperatively. During postoperative care, the patient showed the following improvements in neurological symptoms: GCS score 236, pupil 3 mm prompt/2 mm prompt, and motor grade 3/2 3/2. No specific neurological changes were observed, and a follow-up brain CT was performed 6 days postoperatively. Slight brain swelling was observed compared to that observed in the previous CT; moreover, frontal bone flap dislocation was confirmed with Craniofix^® loosening (FIGURE 2). Consequently, cranioplasty was performed using Microplate and Craniofix^®. After cranioplasty, alignment of the mother bone and bone flap was confirmed. No worsening of the neurological deficits was observed and the patient was discharged.

FIGURE 2. Follow up brain CT and cranioplasty images.

(A-C) Among the 3 Craniofix^®, bone flap dislocation was confirmed by a clamp (yellow arrow) loosening fixed to the right frontal skull. (D) Cranioplasty was performed with Craniofix^®, microplate and screw fixation. Alignment of bone flap and mother bone was confirmed. Also, there was no bone flap dislocation.

DISCUSSION

The Craniofix^® clamp provides a fast, firm, and stable closure connecting the mother bone flap to the craniotomy edge. Unlike a microplate, it can be fixed under the bone flap, so ensuring a more firm fixation. As a disadvantage, if the distance between the mother bones is long, dislocation may occur. Furthermore, contact with the dura mater can occur, potentially leading to adhesion and damage. Some hypotheses can be made as the cause of bone flap dislocation. First, on the skull radiograph (FIGURE 1D), an epidural drain is inserted adjacent to the frontoparietal area of the Craniofix^®. During the process of drain removal, the Craniofix^® may loosen owing to outward force acting on the skull. Second, when fixing the bone flap, instability of the bone flap due to improper positioning of the Craniofix^® clamp cannot be ruled out. As three or four clamps must be balanced around the craniotomy circumference for rigid fixation, the three clamps did not form an angle of 120° during the first operation. Third, owing to brain swelling and fluid collection, Craniofix^® loosening might have occurred as the bone flap was displaced by an increase in ICP. Yoo et al.⁶⁾ reported a case in which cerebral edema progression led to Craniofix^® loosening (TABLE 1). Fourth, bone flap dislocation might have occurred in the process of external shock caused by external factors such as patient transfer or position change.

TABLE 1. Comparison of our case report to first Craniofix^® releasing case.

Study	Hemorrhage	Surgery	Craniofix®	Mechanism of bone flap dislocation
Yoo et al.6)	Acute subdural hemorrhage	Cranioplasty	11 mm, 4ea	Outward force of brain swelling
Our case	Acute subdural hemorrhage	Craniotomy	16 mm, 3ea	Presumed outward force during epidural drain removal

CONCLUSION

If a drain is positioned around the Craniofix^® clamp, it should be carefully removed. When fixing the bone flap, three or four Craniofix^® clamps should be placed at an appropriate angle to receive the load evenly. Furthermore, during bone flap fixation after craniotomy, it would be helpful to drill to trim the bone margins postoperatively, in consideration of possible brain swelling. Finally, it may be optimal to use Craniofix^® in conjunction with other methods simultaneously for bone flap fixation, such as sutures, wires, and microplates.